The following example also available in tutorial-image-display.cpp shows how to create a gray level 3840x2160 image with all the pixels set to 128, and display a red circle with 200 pixel radius in the middle of the image.

Depending on your screen resolution you may just see a part of the image, and certainly not the full red circle.

How to display an image that is larger than the screen resolution

Setting a manual down scaling factor

This other example available in tutorial-image-display-scaled-manu.cpp shows how to modify the previous example in order to introduce a down scaling factor to reduce the size of the display by 5 along the lines and the columns. This feature may be useful to display images that are larger than the screen resolution.

To down scale the display size, just modify the previous example adding the vpDisplay::vpScaleType parameter to the constructor.

Setting an auto down scaling factor

This other example available in tutorial-image-display-scaled-auto.cpp shows now how to modify the previous example in order to introduce an auto down scaling factor that is automatically computed from the screen resolution in order that two images could be displayed given the screen resolution.

To consider an auto down scaling factor, modify the previous example adding the vpDisplay::SCALE_AUTO parameter to the constructor.